1. Field of the Invention
The present invention is directed generally to the field of telecommunication systems, and more particularly, the present invention is directed to a method for transmitting information between network equipment of one or more communication networks and a corresponding communication network.
2. Description of the Related Art
It is known to sequence transactions that relate to the transmission of information according to standardized signalling protocols between network equipment of one or more communication networks. For example, a central signalling system No. 7 (CCS7) employs a signalling protocol and is divided into a plurality of constituent parts in the international cellular mobile radiotelephone network according to the GSM standard (Global System for Mobile Communication). This is supported in the individual countries by respective mobile radiotelephone networks with corresponding network operators. The central signalling system comprises application parts in addition to a user part for telephony at the interface to an ISDN network or a public telephone network. Thus, the mobile application part controls the internal communication between the network equipment of the mobile radiotelephone network or networks. The application part makes one or more signalling procedures available which assume closed control functions.
GSM Specification 09.02, Final Draft, November 1994, pages 38 through 40, discloses a method for declaring the application version that is based on a trial and error method wherein the most supported application version for the network equipment affected by the dialogue and a particular date that indicates the point in time of the support of a higher application version by the respective network equipment are entered in a first table. As soon as the date particular is reached, the currently supported application version is identified as unknown and a branch is made to a second table. The known method assumes that the point in time for the transition to the higher application version supported by the network equipment is known. The entries in the first table are set once by a control function and subsequently remain in a static condition.
In order to set up a dialogue between two network equipment of the mobile radiotelephone networks according to an earlier patent application of the applicant (Serial Number 196 04 049.3-31), a separate message (ENCI, Exchange of Network Capabilities Information) is transmitted during the course of the mutual transmission of information about supported performance features and/or properties of the network equipment. This message serves the purpose of asking whether the function supported by one network equipment are also available in the collaborating network equipment for following dialogues. When this is the case, an entry is made in a table. The entries ensure that information transmission is executed only when the collaborating network equipment supports the function(s). In addition to the necessity of a separate message (ENCI), this method has the disadvantage that, after confirmation of the support of a function by the collaborating network equipment, errors can occur in the network equipment that lead to a disconnect of sub-functions or of the entire function but a correction of the table in the interrogating network equipment is not provided. A signalling with the separate message (ENCI) is no longer possible when an error occurs. Error handling is not provided in the separate message (ENCI).
An object of the present invention is to specify a method with which network equipment can be informed about the functions available in other network equipment in the most simple way while taking into consideration potentially occurring errors.